From: Jaroslav Kysela <perex@perex.cz>
To: "Lu, Brent" <brent.lu@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
Takashi Iwai <tiwai@suse.com>,
Baolin Wang <baolin.wang@linaro.org>,
Arnd Bergmann <arnd@arndb.de>,
Richard Fontana <rfontana@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
paulhsia <paulhsia@chromium.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ALSA: pcm: fix incorrect hw_base increase
Date: Fri, 15 May 2020 11:30:54 +0200 [thread overview]
Message-ID: <ce215f76-89c3-3543-c6ed-bc9b81af50a0@perex.cz> (raw)
In-Reply-To: <BN6PR1101MB21327687327440F1DB7CB75F97BD0@BN6PR1101MB2132.namprd11.prod.outlook.com>
Dne 15. 05. 20 v 11:04 Lu, Brent napsal(a):
>>
>> Is this a bugfix needed for older kernels as well? When did this issue show
>> up?
>>
>> thanks,
>>
>> greg k-h
>
> It happens when DMA stop moving data from host to DSP/DAI for a long time
> (> half of buffer time). I know host driver should do something about it. But if
> not, the HWSYNC will keep increasing the hw_base and hw_ptr and confuses
> user space program.
I'm afraid, but with this code, you turn off the hw_ptr jiffies code. It would
be better to fix the driver in this case (return the updated / estimated DMA
pointer, increase DMA buffer size etc.). This "lag" is unacceptable.
Jaroslav
>
> Regards,
> Brent
>
--
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
next prev parent reply other threads:[~2020-05-15 9:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 4:09 [PATCH] ALSA: pcm: fix incorrect hw_base increase Brent Lu
2020-05-15 7:04 ` Greg Kroah-Hartman
2020-05-15 9:04 ` Lu, Brent
2020-05-15 9:30 ` Jaroslav Kysela [this message]
2020-05-15 10:39 ` Takashi Iwai
2020-05-15 12:01 ` Jaroslav Kysela
2020-05-18 4:38 ` Lu, Brent
2020-05-15 7:21 ` Takashi Iwai
2020-05-15 9:36 ` Lu, Brent
2020-05-15 10:40 ` Takashi Iwai
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